The long-term objectives of this proposed project are to develop a noninvasive procedure for accurate measurement of borderline exocrine pancreatic insufficiency in cystic fibrosis (CF) patients and other disorders affecting exocrine pancreatic function. Our approach is based on simultaneous administration of a 13C-labeled triglyceride (13C-TG), the nonabsorbable marker DyCl3, and the visual fecal marker FD&C Blue #1 (Brilliant Blue, "BB") with a fatty meal followed by collection and analysis of a single sample of stool for 13C-Excess and Dy. These two measurements permit accurate determination of the amount of 13C-TG excreted by the patient without the need for quantitative collection of stools for several days. During Phase-I of the proposed project, we will test the hypothesis that the sensitivity of pancreatic hydrolysis of 13C-TG is strongly influenced by the chain-length of the saturated fatty acids present in the TG. During Phase-II research, we will test a number of 13C-TGs with modified fatty acid characteristics in order to define the effect of TG structure on the sensitivity of the resultant method for specific application to evaluation of borderline exocrine pancreatic insufficiency. PROPOSED COMMERCIAL APPLICATIONS: This research will lead to a noninvasive test for assessment of borderline pancreatic function. It has applications in evaluating cystic fibrosis patients who are pancreatic sufficient but at risk of pancreatic failure.